Balloon catheter

ABSTRACT

A balloon consisting of braided fibers encapsulated between two plastic elastomeric materials affixes to a distal end of a catheter. The braided fibers provide reinforcement to contain pressure and determine the maximum diameter of the balloon on expansion. The elastomeric material provides for fluid containment and collapsing of the balloon after pressurization. An embedded spring in an elastomeric material internal to the catheter provides memory to assist in collapsing the balloon after pressurization. The embedded spring extends from the distal end of the catheter towards the proximal end of the catheter along a substantial length of the catheter. The catheter with the balloon are in a multilumen configuration or in a coaxial configuration. A guidewire passage extends through the elastomeric material with the embedded spring.

CROSS REFERENCES TO CO-PENDING APPLICATIONS

This application is a continuation of U.S. Ser. No. 07/324,913, filedMar. 17, 1989, entitled "Balloon Catheter" to the same assignee, nowU.S. Pat. No. 5,112,304, issued May 12, 1992.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a surgical catheter, and moreparticularly, a balloon catheter for enlargement of restrictions inblood vessels, arteries or other human tissue.

2. Description of the Prior Art

Prior art balloon catheters have utilized numerous types of structuresto expand outwardly to enlarge a restriction such as in a blood vessel,an artery or human tissue, such as the prostrate. One problem in thepast with these structures which enlarged on inflation was that thestructure did not always return to its original diameter or initialcircular configuration.

U.S. Pat. No. 4,456,000 to Sehjeldahl uses a thin rigid material affixedto the distal end of a catheter to form the balloon. Particularly in theuse of non-distensible balloons, the initial profiles achieved bywrapping the balloon are much larger than the outer diameter of thecatheter shaft and after inflation in the body, the resulting collapsedprofile may appear in cross section as a plate extending outward fromthe center of the catheter. This necessitates use of a larger device tointroduce the balloon catheter and presents complication on removal ofthe device from the body and may potentially damage tissue.

U.S. Pat. No. 4,637,396 to Cook uses a knitted balloon in which theknitting changes shape to accommodate balloon expansion. This allows forhigher pressures to be achieved in larger diameter balloons, but doesnot necessarily deal with initial or collapsed profiles.

U.S. Pat. No. 4,702,252 to Brooks uses a braided balloon which changesin length as it expands and is accomplished by a spring at the proximalhub end of the catheter. This design requires relative motion betweenvarious members of the catheter which may be difficult in long lengthand tortuous passageways.

U.S. Pat. No. 4,762,130 to Fogarty uses an embedded spring to lower theprofiles of the balloon. This design also requires relative motion alongits length and does not enhance the pressure changing capability of theelastomeric materials.

The present invention overcomes the disadvantages of the prior art byproviding a balloon catheter with braided fibers encapsulated betweenelastomeric materials and an embedded spring to provide a low balloonprofile after pressurization and depressurization.

SUMMARY OF THE INVENTION

The general purpose of the present invention is to provide a ballooncatheter which has a low profile in a deflated state afterpressurization to a maximum diameter, and has no components which moverelative to one another.

According to one embodiment of the present invention, there is provideda balloon catheter with a hub at a proximal end including a guidewireentry port, an inflation/deflation port and a tube connected to the hub.A guidewire passage and an inflation/deflation passage extend along thelength of the tube. An embedded spring in an elastomeric material orlike material connects to the distal end of the tube. A balloon,including braided fibers encapsulated between an outer elastomericmaterial and inner elastomeric material, connects between the end of thetube and the distal end of the embedded spring member. The catheter canassume either a multilumen configuration or a coaxial configuration.

Significant aspects and features of the present invention include a lowprofile balloon before and after pressurization to its maximum diameter.The differential between the balloon structure and the inner member ofthe catheter is minimal, even after pressurization and subsequentdepressurization because of the combined action of the internal springand the elastomeric material of the balloon. The pliability of theelastomeric material and the spring also provide enhanced steering ofthe catheter during placement due to its extreme flexibility and softtip.

Other significant aspects and features of the present invention is theability to achieve higher balloon pressures, especially in larger sizedballoons used in larger vessels, arteries or tissues.

Further significant aspects and features of the present inventioninclude a braided fiber member which expands to a fixed diameter oninflation with enhanced pressure conveying capability. The braidedfibers assist the balloon to collapse to approximately the same profileafter pressurization. Additionally, there is enhanced cyclic durabilitybecause of the elastomeric materials.

In addition, the use of fibers and elastomeric materials in the balloonconstruction provides for a softer distal tip to the catheter, enhancingsteerability and reducing trauma. In addition, the elastomeric materialprovides a construction which enhances its ability to withstand repeatedcycles of pressurization and depressurization.

In addition, the braid can be made of a radiopaque material obviatingthe need for specific bands for locating the balloon in the body underfluoroscopy.

Lastly, the embedded spring also provides structural integrity againstcollapse of the inner member of the catheter during pressurization ofthe balloon. This enhanced ability allows for movement of the guidewirewhile the balloon is pressurized.

Having thus described embodiments of the present invention, it is aprincipal object hereof to provide a balloon catheter with a balloonusing braided fibers or like materials disposed between an inner and anouter elastomeric layer.

One object of the present invention is to provide a multilumen balloonconfiguration or a coaxial balloon configuration.

Another object of the present invention is to provide a balloon catheterwhich includes internal structure which functions to deflate andcollapse the balloon after pressurization to its maximum diameter. Theballoon with braided fibers between the elastomeric material returns toits normal position, and a spring embedded in an elastomeric material ofthe distal end of the catheter further functions to collapse and returnthe balloon to a normal, deflated position after pressurization. Amaterial with a like function can also be utilized in place of thespring.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects of the present invention and many of the attendantadvantages of the present invention will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, in which like reference numerals designate like partsthroughout the figures thereof and wherein:

FIG. 1 illustrates a perspective view of a multilumen balloon catheter,the present invention;

FIG. 2 illustrates a cross-sectional view of the hub of the multilumenconfiguration;

FIG. 3 illustrates a cross-sectional view of the distal end of themultilumen configuration;

FIG. 4A illustrates a cross-sectional view taken along line 4a--4a ofFIG. 3 of the multilumen configuration;

FIG. 4B illustrates a cross-sectional view taken along line 4b--4b ofFIG. 3 of the multilumen configuration;

FIG. 5 illustrates the expanded balloon of the multilumen configuration;

FIG. 6 illustrates a perspective view of a coaxial balloon catheter, analternative embodiment of the present invention of the coaxialconfiguration;

FIG. 7 illustrates a cross-sectional view of the hub of the coaxialconfiguration;

FIG. 8 illustrates a cross-sectional view of the distal end of thecoaxial configuration;

FIG. 9A illustrates a cross-sectional view taken along line 9a--9a ofFIG. 8 of the coaxial configuration;

FIG. 9B illustrates a cross-sectional view taken along line 9b--9b ofFIG. 8 of the coaxial configuration; and,

FIG. 10 illustrates the expanded balloon of the coaxial configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a perspective view of a multilumen balloon catheter10, the present invention, including a hub 12 at a proximal end 14 withguidewire entry port 16 and an inflation/deflation port 18. Thisparticular multilumen configuration is bilumen. A catheter tube 20connects to the hub 12, and includes a guidewire passage 22 and aninflation/deflation passage 24. A balloon structure 26, as laterdescribed in detail, secures about the distal end 28. A guidewire exit30 is at the distal end 28 of the balloon structure 26.

FIG. 2 illustrates a cross-sectional view of the hub 12 where allnumerals correspond to those elements previously described. The figureillustrates the hub 12 being a molded thermoplastic member engaged aboutthe catheter tube 20, and fused or adhesively secured thereto. The hub12 includes a hub chamber 32, an inflation/deflation port 18, and aguidewire entry port 16. The proximal end of the catheter tube 20secures into one end of the guidewire entry port 16. The hub 12, thecatheter tube 20, the guidewire entry port 16 and theinflation/deflation port 18 are assembled by known processes. Theguidewire passage 22, internal to the catheter tube 20, connects betweenthe guidewire entry port 16 and the balloon structure 26 of FIG. 3. Theinflation/deflation passage 24 connects the balloon structure 26 to theinflation/deflation port 18 through an angled passageway 24a and the hubchamber 32.

FIG. 3 illustrates a cross-sectional view of the distal end 28 of theballoon catheter 10. An embedded spring 38 is embedded or fused intoelastomeric material 40 which connects to the catheter tube 20 at point44, such as by heat fusion or adhesively. The spring can be tensioned toa predetermined degree prior to being embedded in the elastomericmaterial providing a memory for the embedded spring 38 in theelastomeric material. A balloon structure 26, which is coaxial, includesa braided fiber 48 between an inner elastomeric material 50 and outerelastomeric material 52, which is secured about point 54 of the cathetertube 20 and about point 58 of the embedded spring 38 and elastomericmaterial 40 containing the guidewire passage 22, such as by heat fusionor adhesively. The molded tip 58a provides flexibility and softness ofthe catheter.

FIG. 4A illustrates a cross-sectional view taken along line 4a--4a ofFIG. 3 where all numerals correspond to those elements previouslydescribed.

FIG. 4B illustrates a cross-sectional view taken along line 4b--4b ofFIG. 3 where all numerals correspond to those elements previouslydescribed.

FIG. 5 illustrates the balloon catheter 10, and particularly, theballoon structure 26 in an inflated balloon position 46. All numeralscorrespond to those elements previously described. The embedded spring38 is compressed longitudinally and the braided fiber 48 has beenexpanded outwardly so as to enlarge along a substantial portion of itslength centered at approximately the mid-point of the longitudinallength of the braided fibers. The outward expansion of the braidedfibers 48 effectively shortens the length of the balloon 26 in adirection towards the proximal end 14 causing the embedded spring 38 tocompress in a like direction. The braided fibers 48 provide forexpansion to a predetermined diameter for the balloon, and form a cavity60 about the inner surfaces of the balloon structure 26 and the memberwith the embedded spring 38. After deflation of the inflated balloonposition 46 and placing a vacuum on the inflated balloon position 46through the inflation/deflation port 18, the elastomeric materials 50and 52 about the braided fibers 48 in combination, provide forcollapsing of the balloon, as well as the embedded spring 38 returningto a normal resting position. Likewise, the memory of the elastomericmaterial materials 50 and 52 and the embedded spring 38 secondarilyassist the balloon structure in returning to a predetermined collapsedcondition. Materials of known elasticity can be selected such that thebraided fibers or the spring may not be required. The elastomericmaterials can also be selected to have different degrees of elasticityfor expansion and subsequent contraction.

MODE OF OPERATION

Referring to FIGS. 1-5, during a typical procedure, a guidewire isplaced through a body tube or tissue to be dilated, typically an artery.The balloon catheter 10 is then introduced over the guidewire by placingthe distal end 28 of the catheter over the proximal end of a guidewire.The balloon catheter 10 is then moved into a position of restriction bymoving the catheter over the guidewire. Once in position, a syringefilled with a radioopaque fluid is attached to the inflation/deflationport 18 and the syringe plunger moved inward to inflate and pressurizethe inflated balloon position 46 by passing radiopaque fluid through theinflation/deflation passage 24 and into the cavity 60 to expand theballoon structure 26 outwardly to a desired intermediate expansion pointor to a maximum expansion point allowed by the weave structure of thebraided fibers 48. After inflation, a vacuum is introduced into theballoon by moving the plunger outward. The balloon then returns to itsresting position. The catheter is then removed from the body. Theballoon is caused to return to its normal deflated position by thebraided fibers seeking to return to a resting position, the elasticityof the materials and the embedded spring 38.

DESCRIPTION OF THE ALTERNATIVE EMBODIMENTS

FIG. 6 illustrates a perspective view of a coaxial balloon catheter 100,an alternative embodiment of the present invention, including a hub 102at a proximal end 104 with guidewire entry port 106 and aninflation/deflation port 108. A coaxial catheter tube 110 connects tothe hub 102, and includes a guidewire passage 112 and aninflation/deflation passage 114. A balloon structure 116, as laterdescribed in detail, secures about the distal end 118. A guidewire exit120 is at the distal end 118 of the tube 110. The principles of thealternative embodiment are like those as described in FIGS. 1-5.

FIG. 7 illustrates a cross-sectional view of the hub 102 where allnumerals correspond to those elements previously described. The figureillustrates the hub 102 being a molded member engaged about the tube 110and fused or adhesively secured thereto. The hub 102 includes a hubchamber 122, an inflation/deflation port 108, and a guidewire entry port106 secured into the hub 102. The proximal end of the tube 110 securesinto one end of the guidewire entry port 106. The hub 102, the tube 110,the guidewire entry port 106 and the inflation/deflation entry port 108are assembled by known processes. An inner coaxially aligned tube 125forms the guidewire passage 112 and connects between the guidewire entryport 106 and the balloon structure 116 of FIG. 8. Theinflation/deflation passage 114 is formed between the walls of the tube110 and the elastomeric material 125 in a coaxial fashion. Theinflation/deflation passage 114 connects the balloon structure 116 tothe inflation/deflation port 108 through the hub chamber 122 asillustrated in FIG. 8.

FIG. 8 illustrates a cross-sectional view of the distal end 118 of theballoon catheter 100. An embedded spring 124 is embedded in elastomericmaterial 126 which connects to the tube 110 at point 128, such as byheat fusion or adhesive. The embedded spring 124 can be tensioned to apredetermined degree prior to being embedded in the elastomeric materialproviding a memory for the embedded spring in the elastomeric material.A balloon structure 116 which is coaxial includes an inner braided fiber132 between an inner elastomeric material 134 and an outer elastomericmaterial 136, secures about point 138 of the tube 110 and about point140 of the embedded spring 124 and inner elastomeric material 126containing the guidewire passage 112 such as by heat fusion oradhesively. The molded tip 140a provides flexibility and softness of thecatheter.

FIG. 9A illustrates a cross-sectional view taken along line 9a--9a ofFIG. 8 where all numerals correspond to those elements previouslydescribed.

FIG 9B illustrates a cross-sectional view taken along line 9b--9b ofFIG. 8 where all numerals correspond to those elements previouslydescribed.

FIG. 10 illustrates a balloon catheter 100, and particularly the balloon130 in an inflated mode position. All numerals correspond to thoseelements previously described. The operation is similar to that asdescribed for FIGS. 1-5.

Various modifications can be made to the present invention withoutdeparting from the apparent scope hereof.

I claim:
 1. A balloon catheter having physical characteristics and sizesuitable for use in angioplasty comprising:a. a catheter tube having aguidewire passage and an inflation/deflation passage; b. a hub, affixedto the proximal end of said catheter tube, including a guidewire entryport connected to said guidewire passage and an inflation/deflation portconnected to said inflation/deflation passage; c. an elastomeric tube,having a nominal diameter approximating said catheter tube a shortlength relative to said tube, affixed to the distal end of said cathetertube in communication with said guidewire passage to facilitate passageof a guidewire therethrough; d. an annular balloon fixedly secured atthe ends thereof to the outer surface of said elastomeric tube andhaving a port in communication with said inflation/deflation passage ofsaid catheter tube; e. a helical spring, coaxially positioned withrespect to said elastomeric tube within the annulus of said balloon,affixed to said elastomeric tube and adapted to be compressed bylongitudinal shortening of said elastomeric tube induced by radialexpansion of said balloon; and, f. said spring having a longitudinalforce resisting compression for holding said elastomeric tube at apredetermined length to maintain said annular balloon in a smoothtubular shape about said elastomeric tube when said balloon is in thedeflated condition.
 2. A device according to claim 1 wherein saidhelical spring is affixed to said elastomeric tube under partialcompression and is adapted to be further compressed by longitudinalshortening of said elastomeric tube.
 3. A device according to claim 1wherein expansion of said annular balloon causes compression of saidhelical spring.
 4. A device according to claim 1 wherein saidlongitudinal force maintains said balloon in a longitudinally stressedcondition when deflated.
 5. A device according to claim 4 wherein saidballoon is free from folds or wrinkles and provides a smooth externalsurface to the interior wall of a blood vessel when in thelongitudinally stressed condition.
 6. A device according to claim 1wherein said balloon includes reinforcement fibers secured to saiddistal end of said catheter tube and to the distal end of saidelastomeric tube.
 7. A balloon catheter having physical characteristicsand size suitable for use in angioplasty comprising:a. a catheter tubehaving a guidewire passage and an inflation/deflation passage; b. a hub,affixed to the proximal end of said catheter tube, including a guidewireentry port connected to said guidewire passage and aninflation/deflation port connected to said inflation/deflation passage;c. an elastomeric tube, having a nominal diameter approximating saidcatheter tube a short length relative to said tube, affixed to thedistal end of said catheter tube in communication with said guidewirepassage to facilitate passage of a guidewire therethrough; d. an annularballoon fixedly secured at the ends thereof to the outer surface of saidelastomeric tube and having a port in communication with saidinflation/deflation passage of said catheter tube; e. a helical spring,coaxially positioned with respect to said elastomeric tube within theannulus of said balloon, affixed to said elastomeric tube and adapted tobe compressed by longitudinal shortening of said elastomeric tubeinduced by radial expansion of said balloon; f. said spring having alongitudinal force resisting compression for holding said elastomerictube at a predetermined length to maintain said annular balloon in asmooth tubular shape about said elastomeric tube when said balloon is inthe deflated condition; and, g. said helical spring is affixed to saidelastomeric tube under partial compression and is adapted to be furthercompressed by longitudinal shortening of said elastomeric tube.
 8. Aballoon catheter having physical characteristics and size suitable foruse in angioplasty comprising:a. a catheter tube having a guidewirepassage and an inflation/deflation passage; b. a hub, affixed to theproximal end of said catheter tube, including a guidewire entry portconnected to said guidewire passage and an inflation/deflation portconnected to said inflation/deflation passage; c. an elastomeric tube,having a nominal diameter approximating said catheter tube a shortlength relative to said tube, affixed to the distal end of said cathetertube in communication with said guidewire passage to facilitate passageof a guidewire therethrough; d. an annular balloon fixedly secured atthe ends thereof to the outer surface of said elastomeric tube andhaving a port in communication with said inflation/deflation passage ofsaid catheter tube; e. a helical spring, coaxially positioned withrespect to said elastomeric tube within the annulus of said balloon,affixed to said elastomeric tube and adapted to be compressed bylongitudinal shortening of said elastomeric tube induced by radialexpansion of said balloon; f. said spring having a longitudinal forceresisting compression for holding said elastomeric tube at apredetermined length to maintain said annular balloon in a smoothtubular shape about said elastomeric tube when said balloon is in thedeflated condition; and, g. expansion of said annular balloon causescompression of said helical spring.